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Mineral

Magnesium Hydroxide

Also known as: Mg(OH)₂, milk of magnesia, magnesium hydroxide powder

B
Evidence

Magnesium hydroxide is a mineral form of magnesium with established bioavailability for supporting magnesium status and general health. It has mild laxative properties and is commonly used as both a nutritional supplement and an antacid.

Primary uses

  • Magnesium supplementation
  • Muscle and nerve function support
  • Digestive regularity
  • Occasional antacid use

How it works

  • Provides bioavailable magnesium for cofactor roles in enzyme systems
  • Supports muscle relaxation and neuromuscular signaling
  • Increases stool water content via osmotic effect

Dosage

Typical range
200–400 mg elemental magnesium daily (from magnesium hydroxide)
Timing
Can be taken any time of day; often taken with meals to reduce GI upset
With food
May be taken with or without food, though food can reduce laxative effect if constipation relief is not desired
Duration
Safe for long-term use when dosed appropriately; bowel tolerance threshold varies by individual
Special populations
Avoid or limit in those with severe renal impairment; use caution in pregnant women (consult healthcare provider)

Forms

  • Powder· 70/100
  • Capsule· 70/100
  • Liquid suspension· 70/100

Safety

Common side effects

  • Loose stools or diarrhea (dose-dependent)
  • Mild abdominal cramping
  • Nausea at high doses

Contraindications

  • Severe kidney disease or renal failure
  • Bowel obstruction
  • Appendicitis or acute abdomen
  • Concurrent use without medical supervision in those taking bisphosphonates or fluoroquinolone antibiotics

Evidence notes

Magnesium is an extensively researched essential mineral with strong evidence for its physiological role. Magnesium hydroxide specifically has well-established bioavailability and safety as a supplement form, though evidence is primarily observational rather than from large RCTs focused on this particular salt.

Grade B: Some human trials support key claims; further confirmation needed.

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Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider.